RPC consists of five instruments on the Rosetta orbiter that provide a wide variety of complementary information about the plasma environment surrounding Comet 67P/C-G. (Reminder: Plasma is the fourth state of matter, an electrically conductive gas that can carry magnetic fields and electrical currents.)

The instruments are designed to study a number of phenomena, including: the interaction of 67P/C-G with the solar wind, a continuous stream of plasma emitted by the Sun; changes of activity on the comet; the structure and dynamics of the comet’s tenuous plasma ‘atmosphere’, known as the coma; and the physical properties of the cometary nucleus and surface.

But one observation has taken the RPC scientists somewhat by surprise. The comet seems to be emitting a ‘song’ in the form of oscillations in the magnetic field in the comet’s environment. It is being sung at 40-50 millihertz, far below human hearing, which typically picks up sound between 20 Hz and 20 kHz. To make the music audible to the human ear, the frequencies have been increased by a factor of about 10,000.

The music was heard clearly by the magnetometer experiment (RPC-Mag) for the first time in August, when Rosetta drew to within 100 km of 67P/C-G. The scientists think it must be produced in some way by the activity of the comet, as it releases neutral particles into space where they become electrically charged due to a process called ionisation. But the precise physical mechanism behind the oscillations remains a mystery.

“This is exciting because it is completely new to us. We did not expect this and we are still working to understand the physics of what is happening,” says Karl-Heinz.

RPC may also be able to help in tracking Philae’s descent to the surface of 67P/C-G on 12 November, in tandem with the lander’s on-board magnetometer, ROMAP .

The sonification of the RPC-Mag data was compiled by German composer Manuel Senfft (www.tagirijus.de).

Cartesians are in the position of being able to say NO to everything. With all of the advances in physics and observational sciences in the last 400 years, Cartesian doubt has become an inexhaustible well of ego-inflation for every sort of pseudo-skeptic. But they fail to remember that lack of certainty is not the same as certainty of lack. That’s how you can tell a real skeptic from a religious one (yes, skepticism can be a religion).

Sounds to me like solar wind interacting with “bubbles” of ionized gas ejected from the nucleus, assuming that due to the nucleus rotation, the gas cloud is non-uniform (and in a given direction, consists of pulses with the interval of the comet rotation).

That’s fun but let’s be clear – this “singing” scientific value is none. You can speed up (or slow down) just about anything and with suitable speedup/slowdown rate make it “sing”. You can make Earth sing while it revolves around it’s axis too ;).
So it’s just a gimmick for general public, nothing else. It’s good to be aware of this.

I too take scant interest in the “song” as such. It indeed has purely anecdotal value.

I’m highly interested, on the other hand, in the “oscillations in the magnetic field in the comet’s environment” which Claudia refers to and which she explains have been transposed into this “song”.

I note, above all, that the mission scientists are as much surprised by this proof of electromagnetic activity in the comet’s IMMEDIATE environment (nothing to do with the coma here) as they have been, successively, by:
– the unexpectedly irregular, twin-lobed shape of the comet,
-by its completely rocky appearance, with totally jagged outcrops and piles of boulders lying at the foot of towering cliff-faces,
-by the comet’s dominant coal-black colouring, with puzzling whiter spots, patches and ridges all over the surface
-by the relatively smooth “plains” observed extensively on the surface,
-by the total absence of any form of surface-ice,
-by the dead-straight “jets” shooting up mainly from the “neck” region which necessarily receives considerably less sunlight than the “lobes” and should therefore logically be less prone to the hypothesized sublimation/outgassing of similarly hypothesized sub-surface ices,
-by the measured “average” temperature of the comet which is up to an extraordinary 30°C higher than expected,
-by the observed complex electromagnetic interactions between the comet’s coma and the solar wind

The degree of surprise and incomprehension of mission scientists regarding this set of observations is directly proportional to the satisfaction of EU proponents like myself, for whom these observations were not only expected but even predicted within the framework of the EU model.

I concur…I hope the lander portion doesn’t get zapped as it touches the surface. Remember when Nasa shot a projectile at an asteroid? There was a flash right before impact I believe.

It’s funny, they were so wrong about this comet… And they expect me to believe what they say about Black holes and Neutron stars because the chalkboard says so? Get the more mundane objects right before concocting bizarre objects to make your math work.

@Thomas…yes the “song” does not mean much, but it shows us the kind of variation in the magnetic field that is being observed. THAT is the interesting bit.
As you point out, there are a lot of unknowns here, and hopedully as the mission progresses they will become “knowns” – which is the whole point of the exercise.

Could you explain, or link, or some such the explanations of this EU model, that predicts all the things you mention? I agree, some of them are rather obvious, but at the same time, not really, while other are plain speculation until you get to the comet. Also, don’t forget that a lot of this “surprise” is made by the media.

Waclaw, I didn’t get from the article that anything was sped up or slowed down. Basically speaking, they just turned up the volume so humans could hear it. Much like a dog whistle. A dog can hear it but we cannot. We can take your favorite song and play it at the frequency of the “comet song” and you wouldn’t hear it. Then we could reconvert it to human hearing range and you would hear it as designed, no alterations.
While the song itself most likely means absolutely nothing, it does bring questions that will make people look for answers. That process is what leads to great discoveries.
If nothing else, we just might get an award winning sci fi movie from it as imaginations run with the “song”. Many things that were once sci fi, are now a reality, so I wouldn’t discard it just yet as having no scientific value.

Is that an explanation? I still fail to understand how this would turn into sound in the vacuum of space. Maybe I’m just stupid, but I still don’t get it.
Are they using sound to represent the oscillations… I don’t even know how to phrase the question because I don’t get it.

Magnetic fields provide an oscillation, in the same way alternating current in your homes wiring will produce an oscillating field around them. If you put another magnet or something with an electrical current in that field you can take those oscillations and play them through a speaker or make them in to a digital signal.

They’ve transcribed or re-pitched the EM signal from the probe’s magnetometer into a range of frequencies that are audible to our ears, akin to using an infrared camera to see frequencies our eyes cannot. “Sound” is a term being used with some poetic license in this case.

Would be interesting to know whether the track has been sped up by a factor 10000 or some frequency modulation or ‘artistic’ mixing etc. has been applied. 40-50 milliherz corresponds to 20-25 seconds/ cycle, so the hunt for the origin of that periodicity must include: diameter(s) of the nucleus… And henceforth a lot of unnecessesary guessing from my part arises from lack of details 🙂 : has the frequency any relation to nucleus -Rosetta distance? Then some sort of rhythmic discharging between the two bodies can be considered (much to the joy of many of our friends in here i presume!) another interpretation of a 20-25 seconds periodicity could be that is might be caused by a resonant structure emitting gasses (through a tarlike mud comparable to hot springs on earth, like those found on Iceland: gasses released like burps, in which case ‘singing’ would be a euphemism)

First of all, for a signal below 1hz, it would have to be upconverted (multiplied?) so that it’s spectral content would fall between human hearing limits. Then, depending on it’s period it would have to be sped up so it doesn’t get really boring. It would be nice to see a spectrogram of the actual emission. Too many parameters missing to tell what is actually going on here. It’s still pretty exciting though.

Need to talk to the principal investigator on the instrument to get clarification, but they are probably pretty busy right now. I hope we get more explanation.

This is actually why I believe you will never find any “alien” communication on the frequency bands monitored by e.g. the SETI project. No one in his right mind would use a channel that is so full of clutter and “white noise” (all sources combined statistically). Rather these extraterrestrial intelligences will have found a method that would be as unreadable as a few decades ago an FM signal would have been to an AM ham operator!

not very far, since this is not a sound, but magnetic field oscillation, and any three dimensional field decays as 1/r^2, where r is distance. So the intensity falls exponentially. Plus, you would have to be pointing directly at the comet.

Can someone provide a high-level overview of the following?
How was the false sound synthesized? Which on board instruments where listening and how was the detected energy signature mixed with the audio band for our interpretation?

a magnetic field oscillation was recorded. This creates a wave, which can be represented as a modulation of current, which can be manipulated to desirable frequency and strength. Once this is done, just use a speaker.

20 seconds per click, that could be the acoustc wave resonance of the the comet from one far end to the other.
Now if this wave can modulate (magneto resistive) a magnetic field that the instruments detect then the question is what delivers the energy, the solar wind? Elecrtic discharges? Time to make some FFT with the sound track. The big hit is to find what makes this periode so short and still stable. Its intensity varies a lot but not the periode time.

Electromagnetic emissions in the audio band do not exist as sound until they are converted into pressure waves by a transducer like a speaker. It works both ways, we speak in pressure waves in the audio band, our pressure waves need to be converted to electromagnetic energy to be recorded or transmitted.

So, is there some kind of atmosphere on this comet? Otherwise, how is the sound traveling? Sound waves need an atmosphere on which to travel, no sound in a vacuum, space is a vacuum, hence…no sound in space.

Sound waves can travel through solid or liquid as well as air, kind of like measuring the “sound” of earthquakes through subterranean probes. I’m sure earth has a “sound” and we have just recently heard “sounds” the sun makes.

I think it is amazing and I like the poetic reference to “song” because that’s really what it is. So primordial and humbling. With all the bad news in the world, I really felt uplifted about this today. Countries cooperating…WOW!

That was not actual “sound” that was recorded. As you already said, sound waves travel only in matter, not the (relative) vacuum of the space. But! If you read the article, you would notice, that these were “oscillations in the magnetic field” that were recorded. Those are the ones that don’t need any matter to propagate, they do so even better when there is no matter interfering with the field.

I found this quite fascinating. When I first saw this, I couldn’t even think what could be causing the “singing”. At first, I considered that the “singing” may be extraterrestrial in origin, but I read the blog. It’s nothing more than just oscillations in the magnetic field in the comet’s environment.
Orrrrr is it? Lol

THE COMET IS SINGING: READ ABOUT SPINOFF FOR TERRESTRIAL USE OF THIS FINDING…. BETTER HEARING AIDS

I just posted this on my Facebook page. As a person with a severe hearing disability, I was very intrigued by the finding of the comet’s song, especially the
boosting of the sounds 10,000 times to make it audible.

I wish had hearing aids that would be able to do what ESA has done for the comet’s singing. There we go! A real spinoff for earthlings from this type of space research.

Is it possible that this could actually be the equivalent of our media storage devices and and sent out into space by other life forms in an attempt to discover life else where in the universe. Similar to the record we put on Voyager. All we need is the play back device.

Very crazy ..
It is the true sound of the soul essence of all humanity, stored for thousands of years and kilometers that this living organism is to travel the universe. Or is the sound of the voice of the Creator say Amen and tell us remember that we are also eternal

They were not “wrong” about the comet. In the absence of data all we can do is speculate, and usually those speculations prove to be inaccurate. That’s why you have to get more data! There were no surprises when it came to things that we already understood. The trick is to understand the difference between what is speculation and what is well understood. In order to do that one needs to learn the details. Blindly believing everything or blindly disbelieving everything turns out to be equally naive.

That said, what the hell is an “EU model” with respect to a comet? Where are these predictions published? It’s weird to see such a nice summary of interesting things that have been learned followed by rambling nonsense. But there go the comments for you.

Hi all,
Thanks for your great interest in this story. Apologies to those of you who could not listen to the audio track yesterday, it is now back on the blog.

And since many of you asked questions about this ‘sound’ and how it was ‘recorded’, here is a brief clarification.

This track does not contain directly sound waves (vibrations that propagate in a medium) but oscillations of another quantity (the magnetic field) that were measured at the comet and later transformed into a sound track through sonification – a technique used to represent data in an audible form.

Last but definitely not least, a huge thank you to Manuel Senfft (http://www.tagirijus.de), the composer who transformed the data from Rosetta and produced the comet’s ‘song’!

Our Earth has a magnetic field, that which orients compasses. What a compass will not tell you is that there are very small variations in the Earth’s magnetic field which take place at frequencies that can be heard as sound if you understand how to convert magnetic field variations into acoustic sound which we can hear.

On Earth a coil of wire about the size of a ‘Hula Hoop’ and a fairly simple amplifier circuit driving a pair of standard headphones or a loudspeaker will let you hear these normal changes in our magnetic field brought about by a myriad of different activities including distant lightning strikes.

Rosetta has a ‘magnetometer’ on board, a very sensitive, accurate and sophisticated magnetic field detector and as it has neared the comet that detector is finding a fairly slow pulsation in the magnetic field surrounding the comet. That pulsation is so slow that if we played it straight as it comes from the detector it would be too low in frequency for us to hear it. We might play it through a sub-woofer and only know it is there because we could see that the woofer speaker cone is slowly moving in an out.

In order to let us hear this sound it has been ‘sped up.’ A length of the recorded signal is simply played back faster and faster with a variable speed playback system until the frequency of it is high enough that we can hear it with our ears. Digital Music synthesizers do this all the time, sample a sound and play it back at various speeds which correspond to the frequencies of musical notes.

While the scientific value of listening is not considered very high because our perception of the sound cannot be easily measured or quantified any negativism toward the value of this experience may be misguided. Our hearing system is seldom given credit for the amazing sophistication required to hear and understand human speech and music.

I have often wished that this conversion to audible frequencies would happen to other phenomena because we contain quite capable pattern and frequency translators which we understand the sounds of conversation and our environment with. We may find that careful use and study of those translators would allow us new methods of analysis of physical parameters beyond or in addition to our other less subjective methods.

Several things stand out about the Rosetta sound and it is incumbent on the producers to state whether any of the sound has been post-produced or modified, especially the curious ambient echo that makes it sound as though the actual sound source is moving around in some kind of large room. At one point the pulsing almost disappears into the echo as though the source is receding from the detector and then it returns, sounding as though it has approached the detector and is positioned right next to it.

If that is entirely the original signal without any modification after speeding it up then it is perhaps much stranger than we appreciate.

My own suggestion is that the source of this signal is something which when entirely understood will change our lives and our civilization at least as much as the discovery and exploitation of electricity has.

Much like supersonic aircraft cutting through the atmosphere of our planet, maybe it’s creating some sort of interstellar sonic booms?!?! Could it be traveling so fast, that it’s making dark matter collapse as it passes through it?!?! They think dark matter exists everywhere. We just don’t have the ability to see it. I believe the object is traveling fast enough to create such a theoretical sonic boom. As the comment naturally rolls and tumbles through space, it could account for the pitch differential throughout the whole recording.

my main question is with Setti being in service for a number of years… wouldn’t we have heard oscillations in magnetospheres of Hail bop and Haley’s Comet or any other comet?…. supposedly the conspiracy is they started this mission over 25 years ago. Of all the comets out there why this 1 comet? and maybe it’s a dumb coincidence but isn’t rosetta stone the name of a language learning program?what is the significance of the name Rosetta on a project that was started 25 years ago and now they land on a singing rock?. I hate conspiracy theorist but this has me really questioning the entire mission all together…. wouldn’t it be an equal accomplishment to land on Pluto? I feel that they did seek out this one specific mass of rock for a reason… I cannot wait for more developments on the story

All these comments above and about are so much nonsense and the waste of brainpower. Is a tuning fork for eating tuna or a pitchfork for throwing hay? No, it is for discerning the frequency of instruments to the human ear. So my assumption is that this Comet 67p is made of steel and is vibrating as it is hurtling through Space.

I am Denji. About Rosetta’s Singing Comet . This sound is like a continuous tongue movement. It’s acapella. This harmony is consider to be a sound wave emitted from an artificial satellite by the organization of gang stalking. Harmony within 1 minute 30 seconds is like the Japanese TV show “Hamonepu”.

It reminds me a little of a Geiger counter. http://www.youtube.com/watch?v=upPiJ9vOYiY I wonder if it’s not so much detecting oscillations in the magnetic field as it is detecting unevenly dispersed particles with magnetic properties that pass by. That would make some sense, since you wouldn’t expect matter to leave a mobile object in space evenly.

A possible, back-of-an-envelope explanation:
The “singing” is at a frequency of around 50 milli-Hz – that’s one cycle every 20 seconds.
The variations were observed in the magnetic field of the plasma surrounding 67P. That must behave like a gas. The speed of sound in air is about 350 m/S and roughly independent of pressure
67P is about 4km long, so its circumference is 6km (assuming a perfect sphere, which it’s definitely not!). So you’d expect the resonances to be around a 2*350/Pi*4000 Hz for simple modes – i.e. one cycle every 17.95 seconds – not a bad match to one cycle every 20 seconds.
Numerous of unwarranted assumptons, but it’s in the right ball park.

In rough terms, assuming the comet is surrounded by a double layer (DL), I think we can get a relationship between the free electron density inside the DL and the size of the DL.

Assuming the DL behaves like a resonant cavity, the primary frequency of oscillation of the cavity equals the group wave speed divided by the size of the cavity.
.05/sec = v_g/R [v_g = the wave speed; R = the size of the comet Double Layer]

If, however we assume the “singing” oscillations are dominated by free electron oscillations, the frequency of these oscillations is proportional to the square root of the free electron density.
freq = 8980(n_e)^.5
which gives an electron density much lower than the solar wind, so that seems unlikely.

The group velocity route seems more likely, and that will require assuming an electron temperature. One surface measurement gave 120K (I think).

Anyway, you can see how I am thinking about this. Looking for other like-minded folk to help me think it through.

I wonder – if anyone here knows, what order of amplitudes they actually got from the magnetometer measurements? nT? Smaller? 100 km is well within a near-field zone for tens of mHz, must be a reasonable amplitude signal (and what’s the threshold of the magnetometer they used?)

As far as the source of oscillation, you might think of the comet as an electronic inductor-capacitor tank circuit. Each end of the comet could be thought of as capacitive plates, and the material connecting them the inductor. Energy is input from the plasma flow across the comet, and it naturally oscillates at a frequency given by equations at http://en.wikipedia.org/wiki/LC_circuit

I came up with a capacitance of 2e-8 Farads, and inductance of 300k Henries. If this were true, and you simulated a real physical model of it, it might be used to determine internal material characteristics like permeability and conductivity.